Even if you are just a little overweight, it could increase your chances of dying early, according to one of the largest studies ever conducted on health and weight.

The American Cancer Society studied more than 1.5 million healthy people. Overweight white adults were found to be 13 percent more likely to die than those whose weight was in an ideal range.

Doctors said the report only confirms what other studies have found -- that being overweight causes a higher risk of death from heart disease, stroke and cancer.

"Having a little extra meat on your bones - if that meat happens to be fat - is harmful, not beneficial," said Dr. Michael Thun of the American Cancer Society, senior author of the study.

The study's conclusions, published in Thursday's New England Journal of Medicine, are similar to three other large studies, said the lead author, Amy Berrington of the National Cancer Institute.

"Now there's really a very large body of evidence which supports the finding that being overweight is associated with a small increased risk of death," Berrington said.

Two-thirds of U.S. adults are either overweight or obese. Overweight begins at a BMI measurement of 25, obese at 30, and morbidly obese at 40. A 5-foot-6 person is considered overweight at 155 pounds, obese at 186 pounds and morbidly obese at 248 pounds.